<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
  * {
    margin: 0;
    padding: 0;
  }
  .parent {
    width: 500px;
    height: 500px;
    background-color: pink;
  }
  .box {
    width: 100px;
    height: 100px;
    background-color: green;
  }
  .child {
    width: 300px;
    height: 200px;
    background-color: blue;
    position: fixed;
    right: 100px;
    bottom: 100px;
  }
  </style>
</head>
<body>
  <div class="parent"></div>
    <div class="child"></div>
  </div>
  <div class="box">Hello World</div>
</body>
</html>